Needle assembly

Abstract

A needle assembly is disclosed, for use with an injection device. The needle assembly comprises a needle hub (20) having a needle (22) and a needle shield (40) arranged for relative axial movement with respect to the needle hub, between a retracted position in which the tip of the needle projects beyond a forward end of the shield and an extended position in which the tip of the needle does not project beyond the forward end of the shield. The needle shield (40) is axially biased towards the extended position. The needle shield (40) is further arranged to be torsionally biased for relative rotational movement with respect to the needle hub (20).

The invention claimed is: 
     
       1. A needle assembly, for use with an injection device, the needle assembly comprising:
 a needle hub having a needle; 
 a needle shield in direct contact and slidingly engaged with the needle hub such that the needle shield is arranged for relative axial movement with respect to the needle hub, between a retracted position in which the tip of the needle projects beyond a forward end of the shield and an extended position in which the tip of the needle does not project beyond the forward end of the shield; and wherein 
 the needle hub and needle shield are configured such that, when the needle shield is in the extended position, the rearward end of the needle hub is forward of the rearward end of the needle shield. 
 
     
     
       2. A needle assembly as claimed in  claim 1 , wherein the needle shield is longer in the axial direction than the combined axial length of the needle hub and needle. 
     
     
       3. A needle assembly as claimed in  claim 1 , wherein the needle shield extends from a substantially closed forward face having an aperture, through which the needle extends in use, to a substantially open rearward face. 
     
     
       4. A needle assembly as claimed in  claim 3 , wherein the needle hub is captive between the forward and rearward faces of the needle shield. 
     
     
       5. A needle assembly as claimed in  claim 3 , wherein at least one of the faces is provided with a removable closure. 
     
     
       6. A needle assembly as claimed in  claim 1 , wherein the needle shield is provided with a stop proximal to its rearward end to delimit the range of relative axial movement between the needle shield and needle hub, wherein the stop of the needle shield cooperates with a stop on the needle hub. 
     
     
       7. A needle assembly as claimed in  claim 1 , wherein the needle shield has a continuous outer sidewall which encloses the needle hub. 
     
     
       8. A needle assembly as claimed in  claim 1 , wherein the needle assembly is packaged in a flexible airtight wrapping. 
     
     
       9. A needle assembly as claimed in  claim 1 , further comprising a removable cap arranged to seal the needle assembly prior to use, wherein the cap comprises first and second axially spaced apart covers configured, in use, to close the end faces of the needle assembly. 
     
     
       10. A kit comprising:
 a plurality of needle assemblies as claimed in  claim 1 ; 
 a storage tray comprising a plurality of recesses each configured to removably receive a needle assembly. 
 
     
     
       11. A kit according to  claim 10 , wherein each needle assembly is sealingly received into a recess prior to use.